MDC1 and lung cancer: We found the SNP rs4713354A>C that is located in the 5′-untranslated region of MDC1 was significantly associated with lung cancer risk in both populations (P = 0.024), with an odds ratio as 1.23(95% confidence interval  = 1.35–1.26) for the rs4713354C (CA+CC) genotypes compared to the rs4713354AA genotype.